Help with welding problem please

Post by **brian.tabernor** » Tue May 27, 2008 8:38 am

Hi all

I've just got back to trying to get our '59 traveller roadworthy again, the objective getting it on the road for her 50th next year.

The welding I have done on the nearside (new chassis leg, sills, floor pan, rear arch) was all done with gasless fluxed wire and I have stared the same work on the offside. I ran out of wire and bought the normal wire and fitted the convertor to run on full size co2.

My problem is that I can't get any sort of decent weld, all I get is a pop-pop and no penetration even with it turned full up to 130A. (Migmate 130T) The CO2 is getting through ok with no leaks so I don't know what to try. In case it was the wind, I took the welder into the shed and tried on some clean scrap but that made no difference.

Looks like I'll have to go back to gasless wire. (It's in Aldi this Thursday at £10 for 2x0.45kg reels)

Brian

Brian

Post by **alex_holden** » Tue May 27, 2008 9:12 am

Did you remember to reverse the polarity? Is the tip the right size for the wire? co2/argon mix produces a neater weld than plain co2 but it sounds like you have other problems. Full power is much too high for bodywork - I would expect it to blow holes straight through.

Post by **brian.tabernor** » Tue May 27, 2008 11:22 am

alex_holden wrote:Did you remember to reverse the polarity? Is the tip the right size for the wire? co2/argon mix produces a neater weld than plain co2 but it sounds like you have other problems. Full power is much too high for bodywork - I would expect it to blow holes straight through.

Hi Alex

Reverse polarity? Surely there's no difference between gas / gasless MIG welding with regards to polarity.

0.8mm wire, 0.8mm tip

Yes I had expected to blow holes aswell, but I got no penetration at all. Simply swaping to gasless wire produces good welds so what is my problem?

Brian

Post by **alex_holden** » Tue May 27, 2008 11:34 am

I think it's negative tip for gasless and positive tip for MIG.

Post by **bigginger** » Tue May 27, 2008 1:16 pm

brian.tabernor wrote:Reverse polarity? Surely there's no difference between gas / gasless MIG welding with regards to polarity?

There is - no idea why, but it has to be done. Did you alter the wire feed to the correct size for the wire too?

Post by **brian.tabernor** » Tue May 27, 2008 10:18 pm

Thanks Bigginger, Alex

Yes I have adjusted the wire feed and everythinbg is working ok from that end.

I know that arc welding is oposite earth to MIG but there is certainly nothing in the instructions for the MigMate to say polarity should be reversed when swapping to CO2, I'm not even ceratin that it has the ability to swap polarity.

Sorry to doubt but I must make sure before I try.

Brian

Post by **brian.tabernor** » Tue May 27, 2008 10:26 pm

Hi, thanks for your help guys.

I've just been to look at the welder, and in big letters (well big enough not to miss) are the instructions to change polarity for gas welding

. I'll give it a go at the weekend and see how I get on.

It''s good to be working on her again after a three year gap with no time or money.

Brian

Post by **alex_holden** » Tue May 27, 2008 10:32 pm

Welders that are designed to work both with and without gas usually have terminals on the front panel so that you can swap the polarity easily.

You might get a better response to your problem over on the MIG welding forum: http://www.mig-welding.co.uk/forum/index.php

Post by **minor_hickup** » Wed May 28, 2008 9:15 pm

a pop popping sounds like the wire feed is too slow as well, i believe (only hearsay from someone who does have gasless) that the polarity thing doesn't have a massive effect but should be done.

Post by **youngun** » Wed May 28, 2008 11:05 pm

Popping sound usually means wire feed, but seeing as you didnt switch the polarity over that may well be the problem

YG

Post by **britab1967** » Thu May 29, 2008 8:47 pm

Thanks guys, I'll let you know after Saturday when I get the chance to try again.

Brian

Post by **britab1967** » Fri May 30, 2008 10:41 pm

Just to update you.

I've tried it with polarity swapped and it made a little difference but still much worse than with gasless.

Interestingly, quite a few responses on mig-welding.co.uk forum have said the same thing.

http://www.mig-welding.co.uk/forum/show ... php?t=2031

How much difference does the CO2 make against an Argon mix?

Is anyone else achieving good results with the Migmate 130T/0.8mm wire/CO2 mix ?

Back to the gasless Aldi wire for now.

Brian

Post by **rayofleamington** » Sat May 31, 2008 3:48 pm

Is anyone else achieving good results with the Migmate 130T/0.8mm wire/CO2 mix ?

The best I'm getting is average - and that's with many years practise.
When people have borrowed mine they found it much more difficult than their own kit, but that's not always a fair comparison.
With mine I use argon/co2 mix from BOC (very very expensive) so your comments on gasless are interesting.

Post by **XDB** » Wed Jun 04, 2008 10:23 pm

I have struggled with my mig welder on thin metals for years, in fact since I owned it, but thanks to advice from mig weld uk forum It now welds to a satisfactory standard. I started with all settings at their lowest and gently increased each until I got a decent run. If there are holes in the weld its probably a gas problem.

linearaudio · Post by **linearaudio** » Sun Jun 29, 2008 9:39 pm

I had massive feed problems on my SIP. A guy with a boat on the welding forum was advised to tie a rope round his SIP welder, use it as an anchor, and buy a decent make!! Seriously, the feed system has the potential to be complete rubbish, being made largely of inadequately supported plastics, especially if the feed roller has been left wound down tight. The pinch roller can skew round so it will never grip properly, so giving intermittent feed. Also the alignment of the wire entry-pinch-exit can be all over the show. Mine was all the above, but having largely re-engineered the feed system it now feeds a treat at all levels.

Post by **XDB** » Sun Jun 29, 2008 10:13 pm

according to many owners SIP migs are notorious for their poor wire feeds. It's a shame because they seem to very popular and widely available.

Post by **nick69** » Sun Jun 29, 2008 10:34 pm

Mine has a terrible wire feed, even after changing the liner it still happens. Trying to save for a decent machine but other stuff keeps getting in the way!!!

If it helps I always find I have to keep the liner at full stretch when using it, keeps the wire feed problems to a minimum.

Post by **XDB** » Sun Jun 29, 2008 10:45 pm

On the site Mig Weld Uk several people have upgraded the wire feed by either strenthening the wire feed roller mechanism or by wiring a direct feed via a separate transformer to the wire feed motor.

Post by **jonathon** » Sun Jun 29, 2008 11:01 pm

Try a 1mm tip rather than the .8mm and make sure that the shroud is proud of it by at least 5mm, to aid the gas flow. Argonshield light is the best we have used for mig welding, the universal is only used for heavy duty work and is not a good product to use with generally thin car steel.
Do you have much difference in penetration when you wind down the amps, as opposed to full power.
Remember too that on all migs the best results are had with the earth lead as close to the job as possible, and fitted/clamped on to clean bare metal.

Post by **newagetraveller** » Mon Jun 30, 2008 12:09 pm

Shouldn't this thread be in the BODYWORK section?